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  • 1
    ISSN: 1572-8900
    Keywords: solid waste ; composting ; methanogenesis ; degradation ; cellulose acetate ; biodegradability ; anaerobic bioreactor ; biodegradation testing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Cellulose acetate (CA) films with degree of substitution (d.s.) values of 1.7 and 2.5 were exposed to biologically active in-laboratory composting test vessels maintained at approximately 53 °C. The CA 1.7- and 2.5-d.s. films (thickness values of ∼0.5–1.0 and 2.0 mil, respectively) had completely disappeared by the end of 7- and 18-day exposure time periods in the biologically active bioreactors, respectively. The relatively small CA film weight loss observed in the poisoned control test vessels allows the conclusion that CA film erosion during the composting exposures resulted, at least in part, from biologically mediated processes. Under strictly anaerobic conditions, an active methanogenic inoculum was developed by acclimation of a sewage sludge to a synthetic municipal solid waste (SMSW) mixture at 42°C. The CA 1.7-d.s. film samples (0.5- to 1.0-mil thickness) were exposed in anaerobic serum bottles containing a 25% solids loading of SMSW in which methanogenic activity was rapidly established after introducing of the developed inoculum. For exposures of 30 days only small visually distinguishable fragments of the CA 1.7-d.s. films were recovered. In contrast, exposure of the CA 1.7-d.s. film to a poisoned control test vessel resulted in negligible weight loss. Therefore, degradation of the CA 1.7-d.s. films upon exposure to the anaerobic bioreactors was due, at least in part, to biologically mediated processes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 755-762 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The influences of processing variables on the mechanical properties of general grade poly-propylene prepared by oscillating packing injection molding under low pressure were reported. The density as a function of oscillating holding pressure was measured using density gradient columns. The existence of spherulites and shear-induced shish-kebab crystals was confirmed from DSC measurements. The texture of self-reinforced polypropylene was investigated using an X-ray diffractometer and an X-ray flat film camera. Investigations indicate that the mechanical properties of polypropylene can be greatly enhanced using oscillating packing injection molding. The Young's modulus and tensile strength have been enhanced from original 1.4 GPa, 31.0 MPa to 3.0 GPa, 57.8 MPa, respectively. The improvement in mechanical properties is mainly ascribed to perfect spherulites, the existence of shear-induced shish-kebab crystals, and the orientation of molecular chains. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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